The description of the references in this Section is not intended to constitute an admission that any reference referred to herein is “Prior Art” with respect to the Present Invention, unless specifically designated as such.
Medical imaging is important and widespread in the diagnosis of disease. In certain situations, however, the particular manner in which the images are made available to physicians and their patients introduces obstacles to timely and accurate diagnoses of disease. These obstacles generally relate to the fact that each manufacturer of a medical imaging system uses different and proprietary formats to store the images in digital form. This means, for example, that images from a scanner manufactured by General Electric Corp. are stored in a different digital format compared to images from a scanner manufactured by Siemens Medical Systems. Further, images from different imaging modalities, such as, for example, ultrasound and magnetic resonance imaging (MRI), are stored in formats different from each other. Although it is typically possible to “export” the images from a proprietary workstation to an industry-standard format such as “Digital Imaging Communications in Medicine” (DICOM), Version 3.0, several limitations remain as discussed subsequently. In practice, viewing of medical images typically requires a different proprietary “workstation” for each manufacturer and for each modality.
Currently, when a patient describes symptoms, the patient's primary physician often orders an imaging-based test to diagnose or assess disease. Typically, days after the imaging procedure, the patient's primary physician receives a written report generated by a specialist physician who has interpreted the images. The specialist physician, however, typically has not performed a clinical history and physical examination of the patient and often is not aware of the patient's other test results. Conversely, the patient's primary physician typically does not view the images directly but rather makes a treatment decision based entirely on written reports generated by one or more specialist physicians. Although this approach does allow for expert interpretation of the images by the specialist physician, several limitations are introduced for the primary physician and for the patient, such as, for example:                (1) The primary physician does not see the images unless he travels to another department and makes a request;        (2) It is often difficult to find the images for viewing because there typically is no formal procedure to accommodate requests to show the images to the primary physician;        (3) Until the written report is forwarded to the primary physician's office, it is often difficult to determine if the images have been interpreted and the report generated;        (4) Each proprietary workstation requires training in how to use the software to view the images;        (5) It is often difficult for the primary physician to find a technician who has been trained to view the images on the proprietary workstation;        (6) The workstation software is often “upgraded” requiring additional training;        (7) The primary physician has to walk to different departments to view images from the same patient but different modalities;        (8) Images from the same patient but different modalities cannot be viewed side-by-side, even using proprietary workstations;        (9) The primary physician cannot show the patient his images in the physician's office while explaining the diagnosis; and        (10) The patient cannot transport his images to another physician's office for a second opinion.        
It would be desirable to allow digital medical images to be viewed by multiple individuals at multiple geographic locations without loss of diagnostic information.
A similar barrier to accessing medical information exists for researchers interested in studying the effects of medical treatments on populations of patients. Because the medical information is stored in dissimilar digital formats on dissimilar medical information systems, a significant percentage of the overall cost of a research study can be attributed to the effort of extracting and converting the digital records into the format desired by the individual researcher. For research, unlike for clinical care, an additional barrier is introduced by the legal requirements which protect patients' privacy. Widely-recognized strategies to protecting patient privacy are: 1) Seeking each patient's written permission to be studied; and 2) De-Identifying the medical information in such a way that the patient's identity cannot be determined, i.e., by removing the patient's name from the medical information. De-Identification of medical records, while useful, often results in a loss of the information needed to associate multiple records from the same patient with each other (e.g., the patient's name). It would be desirable to allow multiple digital medical records associated with a single patient to be accessed by multiple researchers at multiple geographic locations without violating the patients' right to privacy.
“Teleradiology” allows images from multiple scanners located at distant sites to be transferred to a central location for interpretation and generation of a written report. This model allows expert interpreters at a single location to examine images from multiple distant geographic locations. Teleradiology does not, however, allow for the examination of the images from any site other than the central location, precluding examination of the images by the primary physician and the patient. Rather, the primary physician and the patient see only the written report generated by the interpreters who examined the images at the central location. In addition, this approach is based on specialized “workstations” (which require substantial training to operate) to send the images to the central location and to view the images at the central location. It would be advantageous to allow the primary physician and the patient to view the images at other locations, such as the primary physician's office, at the same time he/she and the patient see the written report and without specialized hardware or software.
In principle, medical images could be converted to Internet Web Pages for widespread viewing. Several technical limitations of current Internet standards, however, create a situation where straightforward processing of the image data results in images which transfer across the Internet too slowly, lose diagnostic information or both. One such limitation is the bandwidth of current Internet connections which, because of the large size of medical images, result in transfer times which are unacceptably long. The problem of bandwidth can be addressed by compressing the image data before transfer, but compression typically involves loss of diagnostic information. In addition, due to the size of the images the time required to process image data from an original format to a format which can be viewed by Internet browsers is considerable, meaning that systems designed to create Web Pages “on the fly” introduce a delay of seconds to minutes while the person requesting to view the images waits for the data to be processed. Workstations allow images to be reordered or placed “side-by-side” for viewing, but again, an Internet system would have to create new Web Pages “on the fly” which would introduce further delays. Finally, diagnostic interpretation of medical images requires the images are presented with appropriate brightness and contrast. On proprietary workstations these parameters can be adjusted by the person viewing the images but control of image brightness and contrast are not features of current Internet standards (such as, for example, http or html).
It is possible to allow browsers to adjust image brightness and contrast, as well as other parameters, using “Java” programming. “Java” is a computer language developed by Sun Microsystems specifically to allow programs to be downloaded from a server to a client's browser to perform certain tasks. Using the “Java” model, the client is no longer simply using the browser to view “static” files downloaded from the server, but rather in addition the client's computer is running a program that was sent from the server. There are several disadvantages to using “Java” to manipulate the image data. First, the user must wait additional time while the “Java” code is downloaded. For medical images, the “Java” code is extensive and download times are long. Second, the user must train to become familiar with the controls defined by the “Java” programmer. Third, the user must wait while the “Java” code processes the image data, which is slow because the image files are large. Fourth, “Java” code is relatively new and often causes browsers to “crash.” Finally, due to the “crashing” problem “Java” programmers typically only test their code on certain browsers and computers, such as Microsoft Explorer on a PC, precluding widespread use by owners of other browsers and other computer platforms.
Wood et al., U.S. Pat. No. 5,891,035 (“Wood”), the contents of which are hereby incorporated by reference in their entirety, describe an ultrasound system which incorporates an http server for viewing ultrasound images over the Internet. The approach of Wood, however, creates Web Pages “on the fly,” meaning that the user must wait for the image processing to complete. In addition, even after processing of the image data into a Web Page the approach of Wood does not provide for processing the images in such as way that excessive image transfer times due to limited bandwidth are addressed or provide for “brightness/contrast” to be addressed without loss of diagnostic information. In addition, the approach of Wood is limited to ultrasound images generated by scanners manufactured by a single company, and does not enable viewing of images from modalities other than ultrasound.
FIG. 1 summarizes a common prior art approach currently used by companies to serve medical images to Internet browsers (e.g., General Electric's “Web-Link” component of their workstation-based “Picture Archiving and Communication System” (PACS)). As can be seen in FIG. 1, serial processing of image data “on the fly” combined with extensive user interaction results in a slow, expensive, and unstable system.
Referring to FIG. 1, after a scanner acquires images (Step 100) a user may request single image as a webpage (Step 200) whereby the image data is downloaded (Step 300) to allow the user to view a single image with the single image (Step 400). Steps 1000-1400 result in extensive user interaction which results in the system being slow, expensive and unstable.
While the Present Invention relates to medical imaging generally, it will be better understood within the discussion of exemplary embodiments directed toward cardiac imaging.